The role of vitamin D: a promising pathway to combat neuropsychiatric lupus disorders.

To evaluate neuropsychiatric manifestations in the pristane-induced lupus (PIL) model, as well as to evaluate immunoregulatory effects of vitamin D (vit-D) in the brain of mice with PIL. Eighty female BALB/c mice were divided into six groups with 90 (3 months) and 180 (6 months) days of experimentation: CO3, CO6 (controls), PIL3, PIL6 (pristane-induced lupus), VD3 and VD6 (PIL supplemented with 1,25-dihydroxyvitamin D). Forced-swim, elevated plus maze and Barnes maze were the behavioral tests performed. Expression of pVDR was assessed by immunofluorescence. Brain IgM and IgG deposits were evaluated by double staining fluorescence. Serum IL-6 and IFN-α1 were quantified by ELISA. AUC-ROC curve was also performed for immunoglobulins. PIL and VD showed depressive-like behavior in the forced-swim test and anxious-like behavior in the elevated plus maze test. PIL also presented cognitive and memory impairment in the Barnes maze test. Additionally, PIL and VD presented higher levels of serum IFN-α1, but not IL-6. Mice supplemented with vit-D had reduced IgM and IgG deposits and increased pVDR expression in the brain after 180 days. The AUC-ROC curve demonstrated high sensitivity and specificity for IgM and IgG in the brain. We observed neuropsychiatric manifestations in this model of systemic lupus erythematosus (SLE), strongly corroborating to PIL model being suitable as a neuropsychiatric lupus (NPSLE) model. Vit-D was able to reduce immunoglobulin deposits in the brain and influenced the levels of serum IL-6 in the animals assessed. Also, it improved memory, but it had no effect on depressive and anxious-like behavior.